Highly Enantioselective Insertion of Carbenoids into N−H Bonds Catalyzed by Copper Complexes of Chiral Spiro Bisoxazolines

A highly efficient copper-catalyzed asymmetric insertion of α-diazoesters into N−H bonds has been realized by using chiral spiro bisoxazoline ligands, affording α-amino acid derivatives in high yields with excellent enantioselectivities.